Fix ANGLE config (take 2)

Bot was failing with:

"sequence item 7: expected string, int found"

R=borenet@google.com

Author: robertphillips@google.com

Review URL: https://codereview.chromium.org/292313002

git-svn-id: http://skia.googlecode.com/svn/trunk@14834 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/tools/bench_pictures.cfg b/tools/bench_pictures.cfg
index 2628e50..d11377e 100644
--- a/tools/bench_pictures.cfg
+++ b/tools/bench_pictures.cfg
@@ -64,8 +64,8 @@
 msaa16 = Config(config='msaa16', viewport=[str(DEFAULT_VIEWPORT_X),
                                            str(DEFAULT_VIEWPORT_Y)])
 
-viewport_angle = Config(config='angle',
-                        viewport=[DEFAULT_VIEWPORT_X, DEFAULT_VIEWPORT_Y])
+viewport_angle = Config(config='angle', viewport=[str(DEFAULT_VIEWPORT_X),
+                                                  str(DEFAULT_VIEWPORT_Y)])
 
 # This dictionary defines the sets of configs for all platforms. Each config is
 # a dictionary of key/value pairs directly corresponding to the command-line